Cassette lid opening device

ABSTRACT

A cassette lid opening device for use in a clean room apparatus configured for cooperation with a wafer cassette. The cassette lid opening device comprises a wall structure having a separation wall having a wall opening for transferring wafers therethrough, a cassette docking port, and a lid handler provided to the wall structure. The cassette docking port is arranged at a first side of the wall structure for docking a wafer cassette. The lid handler is movable relative to the wall opening and configured to engage a cassette lid of the wafer cassette docked in the cassette docking port. The cassette lid opening device further comprises a blower having an elongated, slit-like nozzle substantially spanning a height or a width of the wall opening and configured to blow a curtain-shaped jet stream of a purge gas into a cassette interior of the wafer cassette.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/881,158 filed Jul. 31, 2019 titled CASSETTE LID OPENINGDEVICE, the disclosure of which is hereby incorporated by reference inits entirety.

FIELD OF THE DISCLOSURE

The present disclosure generally relates to a cassette lid openingdevice for use in a clean room apparatus.

BACKGROUND

Wafer cassettes are used in clean room environments to transport wafersto and from clean room apparatuses, such as vertical batch furnaces. Anexample of such a wafer cassette is the Front Opening Unified Pod, orFOUP, which is used to transport 300 mm wafers. A wafer cassette may beplaced against a lid opening device which may be arranged at an openingin a wall of the clean room apparatus. The opening in the wall may becloseable by means of a door. The wall may, for example, separate afirst environ, e.g., a cassette handling space, from a secondenvironment, e.g., a wafer handling space. The lid opening device may beconfigured to open the lid of the wafer cassette and the door, whilstalso preventing particles/contaminations from entering the wafercassette and/or the second environment. Since wafer cassettes are notairtight, they may be filled with clean room air which is present in theclean room environment. When the second environment of the clean roomapparatus uses a purge gas, such as nitrogen (N₂), for example to reducethe levels of O₂/H₂O within the second environment, it is preferablethat the clean room air in the wafer cassette be at least partly removedbefore the door may be opened.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

It is an object to obtain a desired concentration level of purge gaswithin the wafer cassette relatively quick with a minimum amount ofpurge gas to be spent.

To that end, there may be provided a cassette lid opening device. Moreparticularly, there may be provided a cassette lid opening device foruse in a clean room apparatus configured for cooperation with a wafercassette. The wafer cassette may comprise a cassette body defining acassette interior for accommodating wafers and may have a cassetteopening which is closeable with a cassette lid. The cassette lid openingdevice may comprise a wall structure, a cassette docking port, and/or alid handler provided to the wall structure. The wall structure may havea separation wall having a first side bounding a first space and havingan opposite second side bounding a second space. The separation wall mayhave a wall opening for transferring wafers therethrough. The cassettedocking port may be arranged at the first side of the wall structure fordocking a wafer cassette which is accommodated in the first space. Thelid handler may be movable relative to the wall opening and may beconfigured to engage the cassette lid of the wafer cassette docked inthe cassette docking port. The lid handler may have a closed position inwhich the engaged cassette lid closes off the cassette body. The lidhandler may have an open position in which the engaged cassette lid isspaced apart from the cassette body. The cassette lid opening device mayfurther comprise an air pressure flow generator, e.g., a blower, havingan elongated, slit-like nozzle substantially spanning a height or awidth of the wall opening and may be configured to blow a curtain-shapedjet stream of a purge gas away from the separation wall in the directionof the first space into the cassette interior.

There may also be provided an assembly for use in a clean roomapparatus. The assembly may comprise a wafer cassette which may have acassette body and a cassette lid. The cassette body may define acassette interior for accommodating wafers and may have a cassetteopening. The cassette lid may be configured to close off the cassetteopening. The assembly may further comprise the cassette lid openingdevice according to the description.

The present disclosure may also provide a method for opening and purginga wafer cassette. The method may comprise providing a wafer cassettewhich may include a cassette body defining a cassette interior foraccommodating wafers, and which may have a cassette opening. The wafercassette may further comprise a cassette lid for closing off thecassette opening. The method may further comprise moving the cassettelid with respect to the cassette body to an opened position to open thewafer cassette, and may comprise purging the cassette interior byblowing a curtain-shaped jet stream of a purge gas into the cassetteinterior while moving the curtain-shaped jet stream along substantiallythe entire width or height of the cassette opening.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain objects and advantages of the invention havebeen described herein above. Of course, it is to be understood that notnecessarily all such objects or advantages may be achieved in accordancewith any particular embodiment of the invention. Thus, for example,those skilled in the art will recognize that the invention may beembodied or carried out in a manner that achieves or optimizes oneadvantage or group of advantages as taught or suggested herein withoutnecessarily achieving other objects or advantages as may be taught orsuggested herein.

Various embodiments are claimed in the dependent claims, which will befurther elucidated with reference to an example shown in the figures.The embodiments may be combined or may be applied separate from eachother.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments will becomereadily apparent to those skilled in the art from the following detaileddescription of certain embodiments having reference to the attachedfigures, the invention not being limited to any particular embodiment(s)disclosed.

BRIEF DESCRIPTION OF THE FIGURES

While the specification concludes with claims particularly pointing outand distinctly claiming what are regarded as embodiments of theinvention, the advantages of embodiments of the disclosure may be morereadily ascertained from the description of certain examples of theembodiments of the disclosure when read in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a top sectional view of an example of an assembly accordingto the description;

FIG. 2 shows the example of FIG. 1 with the lid handler in an openposition in front of the wall opening, and with the jet stream of thepurge gas at the left-hand side not yet being blown into the cassetteinterior;

FIG. 3 shows the example of FIGS. 1 and 2 with the lid handler movedlaterally to the right, parallel to the separation wall, and with thejet stream being blown into the cassette interior at the left-hand sideof the cassette body;

FIG. 4 shows the example of FIGS. 1-3 with the lid handler moved morelaterally to the right, with the jet stream also being blown into thecassette interior more to the right, and with an area of purge gas tothe left of the jet stream;

FIG. 5 shows the example of FIGS. 1-4 with the lid handler moved evenmore laterally to the right, with the jet stream being blown into thecassette interior at the right-hand side of the cassette body, and withthe area of purge gas fully occupying the cassette interior.

DETAILED DESCRIPTION OF THE FIGURES

In this application similar or corresponding features are denoted bysimilar or corresponding reference signs. The description of the variousembodiments is not limited to the example shown in the figures and thereference numbers used in the detailed description and the claims arenot intended to limit the description of the embodiments, but areincluded to elucidate the embodiments by referring to the example shownin the figures.

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below. The illustrationspresented herein are not meant to be actual views of any particularmaterial, structure, or device, but are merely idealized representationsthat are used to describe embodiments of the disclosure.

As used herein, the term “wafer” may refer to any underlying material ormaterials that may be used, or upon which, a device, a circuit, or afilm may be formed.

In the most general term the present disclosure provides a cassette lidopening device 12 for use in a clean room apparatus configured forcooperation with a wafer cassette 80. The wafer cassette 80 may comprisea cassette body 82 defining a cassette interior 88 for accommodatingwafers and may have a cassette opening 86 which is closeable with acassette lid 84. The cassette lid opening device 12 may comprise a wallstructure 14, a cassette docking port 28, and a lid handler 30 providedto the wall structure 14. The wall structure may have a separation wall16 having a first side 18 bounding a first space 22 and having anopposite second side 20 bounding a second space 24. The separation wall16 may have a wall opening 26 for transferring wafers therethrough. Thecassette docking port may be 28 arranged at the first side 18 of thewall structure 14 for docking a wafer cassette which is accommodated inthe first space 22. The lid handler 30 may be movable relative to thewall opening 26 and may be configured to engage the cassette lid 84 ofthe wafer cassette 80 docked in the cassette docking port 28. The lidhandler 30 may have a closed position in which the engaged cassette lid84 closes off the cassette body 82. The lid handler 30 may have an openposition in which the engaged cassette lid 84 is spaced apart from thecassette body 82. The cassette lid opening device 12 may furthercomprise an air pressure flow generator, e.g., a blower 36, having anelongated, slit-like nozzle 38 substantially spanning a height or awidth of the wall opening 26 and may be configured to blow acurtain-shaped jet stream 40 of a purge gas away from the separationwall 16 in the direction of the first space 22 into the cassetteinterior 88.

By virtue of the air pressure flow generator or blower 36 beingconfigured to blow a curtain-shaped jet stream 40 of the purge gas intothe cassette interior 88, the purge gas jet stream 40 forms a front ofpurge gas which blows the clean room air away. Because the jet steam isa curtain-shaped jet stream 40, it may divide the cassette interior intotwo area's 90, 92, i.e. one area on either side of the curtain-shapedjet stream. Because the nozzle 38 of the blower 36 is an elongated,slit-like nozzle 38 substantially spanning the height or width of thewall opening 26, the jet stream 40 may also span the cassette interior88 from one end to an opposite end. Because sides of the jet stream 40thus flow past the sides of the cassette body 82, clean room air in thecassette interior 88 may not pass these sides of the jet stream 40,making a distinct division between the area's 90, 92 on both sides ofthe curtain-shaped jet steam possible, with no flows of air from onearea to the other. The speed with which the jet stream 40 is blown intothe cassette interior 88 may be adapted in dependence of a size height,or width of the wall opening 26 and a depth of the cassette interior 88.In this way, the jet stream front may drive off the clean room air andreplace it with the purge gas. Because the wafers are usually orientatedhorizontally within the cassette interior, the nozzle 38 advantageouslyspans the height of the wall opening 26, i.e. spans the wall opening 26in a vertically orientated direction. Because the purge gassubstantially does not mix with the clean room air, less purge gas isneeded to replace the air in the wafer cassette 80 than with a methodwhich is based on ‘mixing and diluting’ the clean room air present inthe wafer cassette 80 with purge gas. Not only less purge gas is needed,also the purge time may be reduced.

In an embodiment, the blower 36 may be constructed and arranged moveablealong substantially the entire width or height of the cassette opening86 and may be configured to blow into the cassette interior 88. The lidhandler 30 may be configured to move the engaged cassette lid 84laterally, parallel to the separation wall 16. The blower 36 may beconnected to the lid handler 30 and may be configured to blow past theengaged cassette lid 84 into the cassette interior 88.

By connecting the blower 36 to a laterally movable lid handler 30, thejet stream may move laterally together with the lid handler 30. Thisensures that the jet stream front may move from one side of the cassetteinterior 88 to another, opposite side, thereby driving off and pushingaway the clean room air in the cassette interior 88. An example of howthis may work is shown in FIGS. 2-5. Suppose for instance that thecassette interior 88 is bounded by a square or rectangular form having abottom wall, top wall and two side walls. The curtain-shaped jet steam40 may than span the cassette interior 88 from the bottom wall to thetop wall thereby dividing the cassette interior 88 into a left side area90 and a right side area 92. At the onset of the purging the entirecassette interior 88 is filled with clean room air, as can be seen inFIG. 2. The purging will then start with the jet stream 40 blowing alongthe left or right side wall of the cassette interior 88. Suppose the jetsteam is initially blown pas the left side wall of the cassette interior88, as can be seen in FIG. 3. The clean room air is than restricted tothe area 92 on the right-hand side of the jet stream 40. The lid handler30 and thus the jet stream 40 may subsequently travel to the right. Bydoing this the area 92 on the right of the jet stream 40, which isfilled with the clean room air will gradually become smaller, while atthe same time the area 90 on the left of the jet stream 40, willgradually become bigger, as can be seen in FIG. 4. Eventually the jetstream 40 will have reached the right side wall of the cassette interior88 and all of the clean room air will have been driven out of thecassette interior, as can be seen in FIG. 5.

In an embodiment, the blower 36 may comprise a convex surface 42. Theelongated, slit-like nozzle 38 may be configured to blow the jet stream40 over the convex surface 42. The cassette lid opening device 12 mayfurther be provided with a second purge gas source 44 supplying a secondpurge gas in the surrounding of the convex surface 42, such that as aresult of the Coand{hacek over (a)} effect at least part of the suppliedsecond purge gas is entrained by the jet stream 40 of purge gas beingblown over the convex surface 42.

The Coand{hacek over (a)} effect is the tendency of a jet stream 40 tostay attached to a convex surface 42. When blown over the convex surface42, the Coand{hacek over (a)} effect creates an underpressure at anopposite side of the jet stream 40 with respect to the convex surface42. Ambient gas is entrained to the jet stream 40 because of thisunderpressure. Because of this entrainment the effect of the blower 36is amplified and a very uniform flow of the jet stream 40 is created.The convex surface 42 over which the jet stream 40 is blown thus makesan ideal injector with a uniform outflow.

In an embodiment, the blower 36 may be configured to blow thecurtain-shaped jet stream 40 of the purge gas substantially across anentire depth of the cassette body 82.

By making sure the jet stream 40 is blown across the entire depth of thecassette body 82, the jet stream 40 will reach the far end of thecassette body 82, opposite the cassette opening 86. Hereby the cleanroom air is prevented from circumventing the jet stream 40 at this farend to reach the area 90 in the cassette interior 88 which is alreadypurged.

In an embodiment, the wall structure 14 may comprise an exhaust port 46.The exhaust port 46 may be configured to remove a gas from the cassetteinterior 88 when the lid handler 30 is being moved from the closed tothe open position and when the lid handler 30 is in the open position.The exhaust port 46 may comprises a venturi.

The exhaust port 46 prevents the accumulation of gas in the cassetteinterior 88. The exhaust port 46 is preferably placed at a locationtowards which the jet stream 40 drives the clean room air. In theexample depicted in the figures this is near the right side wall of thecassette body 82.

In an embodiment, the cassette lid opening device 12 may furthercomprise a door 48 and a door handler 50. The door 48 may be configuredto close off the wall opening 26 in the separation wall 16 and may bemoveable with respect to the wall opening 26. The door handler 50 may beconnected to the door 48. The door handler 50 may be configured to movethe door 48 to a closed position in which in which the door 48 closesoff the wall opening 26, and an open position in which the door is movedlaterally away from the wall opening 26.

In an embodiment, the door handler 50 may be connected to the lidhandler 30 so as to move laterally together.

Because the jet stream 40 blows drives off or blows away the clean roomair in the cassette interior 88, this clean room air is prevented fromreaching the second space 24 on the opposite side of the separation wall16 and door 48. The door 48 does therefore not need to stay closed untilall of the clean room air is purged from the cassette interior 88. Thedoor 48 may already be opened during the purging and the door 48 maymove together with the lid handler 30. Because the opening of the door48 does not occur subsequent to the moving of the lid handler 30 butsimultaneously, time is saved. This may have a positive effect of thethroughput of the clean room apparatus of which the cassette lid openingdevice may be part of.

In an embodiment the second space 24 may be a minienvironment of theclean room apparatus.

The present disclosure also provides an assembly 10 for use in a cleanroom apparatus, of which an example is shown in FIGS. 1-5. The assembly10 may comprise a wafer cassette 80. The wafer cassette 80 may comprisea cassette body 82 and a cassette lid 84. The cassette body 82 maydefine a cassette interior 88 for accommodating wafers and may have acassette opening 86. The cassette lid 84 may be configured to close offthe cassette opening 86. The assembly 10 may further comprise thecassette lid opening device 12 according to the description.

The effects and advantages of the assembly 10 are similar to theadvantages described above in relation to the cassette lid openingdevice and these effects and advantages are inserted here by reference.

In an embodiment, the wafer cassette 80 may comprise a Front OpeningUnified Pod (FOUP). The FOUPs are dimensioned according to a standardand are used for 300 mm wafers. This may increase the exchangeability ofthe cassette lid opening device for use with wafer cassettes fromdifferent manufacturers. It may also increase the exchangeability of thecassette lid opening device for use in clean room apparatuses ofdifferent manufactures.

The present disclosure may also disclose a method for opening andpurging a wafer cassette 80. The method may comprise providing a wafercassette 80 having a cassette body 82 defining a cassette interior 88for accommodating wafers and having a cassette opening 86. The wafercassette 80 may further comprise a cassette lid 84 for closing off thecassette opening 86. The method may further comprise moving the cassettelid 84 with respect to the cassette body 82 to an opened position toopen the wafer cassette 80, and may comprise purging the cassetteinterior 88 by blowing a curtain-shaped jet stream 40 of a purge gasinto the cassette interior 88 while moving the curtain-shaped jet stream40 along substantially the entire width or height of the cassetteopening 86.

The effects and advantages of the method are similar to those describedwith reference to the lid opening device an which are incorporated hereby reference.

In an embodiment, the purging may be effected at least during the movingof the cassette lid 84. The moving of the curtain-shaped jet 40 alongsubstantially the entire width or height of the cassette opening 86 andthe moving of the cassette lid 84 may be coupled movements.

The purging may be effected by the cassette lid opening device 12according to the description. The effect of purging the cassetteinterior 88 during the moving of the cassette lid 84 is described inrelation to the device 12 with the feature that the lid handler 30 maybe configured to move the engaged cassette lid 84 laterally, parallel tothe separation wall 16. The same effects and advantages mentioned therealso apply to this embodiment of the method.

Although illustrative embodiments of the present invention have beendescribed above, in part with reference to the accompanying drawings, itis to be understood that the invention is not limited to theseembodiments. Variations to the disclosed embodiments can be understoodand effected by those skilled in the art in practicing the claimedinvention, from a study of the drawings, the disclosure, and theappended claims.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure or characteristicdescribed in connection with the embodiment is included in at least oneembodiment of the present invention. Thus, the appearances of thephrases “in one embodiment” or “in an embodiment” in various placesthroughout this description are not necessarily all referring to thesame embodiment.

Furthermore, it is noted that particular features, structures, orcharacteristics of one or more of the various embodiments which aredescribed above may be used implemented independently from one anotherand may be combined in any suitable manner to form new, not explicitlydescribed embodiments. The reference numbers used in the detaileddescription and the claims do not limit the description of theembodiments nor do they limit the claims. The reference numbers aresolely used to clarify.

LEGEND

-   10—assembly-   12—cassette lid opening device-   14—wall structure-   16—separation wall-   18—first side-   20—second side-   22—first space-   24—second space-   26—wall opening-   28—cassette docking port-   30—lid handler-   36—blower-   38—nozzle-   40—jet stream-   42—convex surface-   44—second purge gas source-   46—exhaust port-   48—door-   50—door handler-   80—wafer cassette-   82—cassette body-   84—cassette lid-   86—cassette opening-   88—cassette interior-   90—area filled with purge gas-   92—area filled with clean room air

1. A cassette lid opening device for use in a clean room apparatusconfigured for cooperation with a wafer cassette, wherein the wafercassette comprises a cassette body defining a cassette interior foraccommodating wafers and having a cassette opening which is closeablewith a cassette lid, wherein the cassette lid opening device comprises:a wall structure having a separation wall having a first side bounding afirst space and having an opposite second side bounding a second space,the separation wall having a wall opening for transferring waferstherethrough; a cassette docking port arranged at the first side of thewall structure for docking a wafer cassette which is accommodated in thefirst space; and a lid handler provided to the wall structure, movablerelative to the wall opening and configured to engage the cassette lidof the wafer cassette docked in the cassette docking port, the lidhandler has a closed position in which the engaged cassette lid closesoff the cassette body, and an open position in which the engagedcassette lid is spaced apart from the cassette body, the cassette lidopening device further comprising a blower having an elongated,slit-like nozzle substantially spanning a height or a width of the wallopening and configured to blow a curtain-shaped jet stream of a purgegas away from the separation wall in the direction of the first spaceinto the cassette interior.
 2. The cassette lid opening device accordingto claim 1, wherein the blower is constructed and arranged moveablealong substantially the entire width or height of the cassette openingand configured to blow into the cassette interior.
 3. The cassette lidopening device according to claim 1, wherein the lid handler isconfigured to move the engaged cassette lid laterally, parallel to theseparation wall, and wherein the blower is connected to the lid handlerand is configured to blow past the engaged cassette lid into thecassette interior.
 4. The cassette lid opening device according to claim1, wherein the blower comprises a convex surface and wherein theelongated, slit-like nozzle is configured to blow the jet stream overthe convex surface.
 5. The cassette lid opening device according toclaim 4, further provided with a second purge gas source supplying asecond purge gas in the surrounding of the convex surface, such that asa result of the Coand{hacek over (a)} effect at least part of thesupplied second purge gas is entrained by the jet stream of purge gasbeing blown over the convex surface.
 6. The cassette lid opening deviceaccording to claim 1, wherein the blower is configured to blow thecurtain-shaped jet stream of the purge gas substantially across anentire depth of the cassette body.
 7. The cassette lid opening deviceaccording to claim 1, wherein the wall structure comprises an exhaustport configured to remove a gas from the cassette interior when the lidhandler is being moved from the closed to the open position and in theopen position.
 8. The cassette lid opening device according to claim 7,wherein the exhaust port comprises a venturi.
 9. The cassette lidopening device according to claim 1, further comprising: a doorconfigured to close off the wall opening in the separation wall andbeing moveable with respect to the wall opening; a door handlerconnected to the door and configured to move the door to: a closedposition in which in which the door closes off the wall opening; and anopen position in which the door is moved laterally away from the wallopening.
 10. The cassette lid opening device according to claim 9,wherein the door handler is connected to the lid handler so as to movelaterally together.
 11. The cassette lid opening device according toclaim 1, wherein the second space is a minienvironment of the clean roomapparatus.
 12. An assembly for use in a clean room apparatus,comprising: a wafer cassette comprising: a cassette body defining acassette interior for accommodating wafers and having a cassetteopening; and a cassette lid configured to close off the cassetteopening; and the cassette lid opening device according to claim
 1. 13.The assembly according to claim 12, wherein the wafer cassette comprisesa FOUP.
 14. A method for opening and purging a wafer cassette,comprising; providing a wafer cassette comprising a cassette bodydefining a cassette interior for accommodating wafers and having acassette opening, the wafer cassette further comprising a cassette lidfor closing off the cassette opening; moving the cassette lid withrespect to the cassette body to an opened position to open the wafercassette; and purging the cassette interior by blowing a curtain-shapedjet stream of a purge gas into the cassette interior while moving thecurtain-shaped jet stream along substantially the entire width or heightof the cassette opening.
 15. The method according to claim 14, whereinthe purging is effected at least during the moving of the cassette lid,wherein the moving of the curtain-shaped jet stream along substantiallythe entire width or height of the cassette opening and the moving of thecassette lid are coupled movements.